1) Field of the Invention
The invention herein relates to shelving and similarly configured systems, specifically a multi-purpose tubular frame structure.
2) Description of the Prior Art
Conventional and typical arrangements of assembly-type furniture structures:    (1) As indicated in FIG. 1 and FIG. 2, the isometric drawing of a conventional shelf rack and the exploded drawing of a section of the conventional shelf rack, a conventional shelf rack A consists of corner posts A1 and shelves A2 that are assembled together by means of tightened threaded fasteners A3 and, as such, since the shelves A2 are fixed in place after assembly, the height of the shelves A2 cannot be conveniently adjusted. When the user wants to vary the shelf height, tools must be utilized to disassemble the shelf rack and then re-assemble it once again following re-positioning; as a result, the height adjustment task is time consuming and, furthermore, complicated, which is a drawback.    (2) As indicated in FIG. 3, FIG. 4, and FIG. 5, the isometric drawing of a conventional bed, the exploded drawing of the conventional bed, and the isometric drawing of a section of conventional bed shown in a partial, magnified view, a conventional bed B is comprised of a mattress B1, a cushioning layer B2, and a frame B3, the frame B3 consisting of a plurality of square tubes B31 and support posts B3 that are welded together, with the cushioning layer B2 and the mattress B1 then situated on the frame B3. As such, since the frame B3 is welded into a permanent structure, when the conventional bed is shipped, it easily occupies more square area that adversely affects delivery and storage by increasing shipping costs, which are generally passed on to consumers, a situation that is not ideal and illustrates another drawback.
In view of the various shortcomings and inconveniences of the said conventional assembly-type furniture, the applicant of the invention herein undertook continuous research and development to remedy the drawbacks, enhance the marketability of the product, and further improve its functional utility, which culminated in the successful completion of the structure of the invention herein and the submitting of a new patent application.